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1.
Abstract

A watershed‐based approach to water quality management is necessary for protecting coastal water quality, but the relative importance of inland pollution sources on estuaries is often overestimated. This can lead to a misallocation of coastal water protection resources and ignorance of coastal zone pollution sources. This overestimation of upstream contributions is attributable to a failure to recognize that many estuaries have little or no inland drainage area, the confusion of basinwide pollutant loading with pollutant delivery to estuaries, the low delivery ratios for many pollutants within drainage basins, and disproportionately high pollutant delivery for sources within the coastal zone. Examples are given from North Carolina. As a general rule, resources expended on pollution control within or near the coastal zone will result in more coastal water quality improvement per unit effort than resources expended upstream.  相似文献   

2.
Abstract

This paper presents an analysis of the findings of a survey of a sample of Beaufort county, South Carolina, households which was conducted to ascertain preferences for environmental quality. These preferences were approximated from survey responses on willingness to pay for environmental amenities and the size of payments households would require to forfeit them. A scale was developed and used to rank these responses ordinally, and the matrices of scaled responses for each of eight household annual‐income classes were subjected to factor analyses.  相似文献   

3.
Presenteeism research has only recently extended from a construct capturing lost productivity due to attending work despite health issues to a construct representing students’ perceived academic performance. Aligning with presenteeism’s prevalent research paradigm, the pioneering studies used health-related issues to measure presenteeism. In contrast, this study used the Presenteeism and Perceived Academic Performance (PPAP) Scale, which the researcher developed for this study. The PPAP Scale comprises aspects of student behavior that support academic performance. This study filled gaps in the literature by investigating presenteeism as a concept associated with students’ perceived academic performance, measured with the PPAP Scale, and factors specific to maritime education. The factors investigated were self-identified by the study respondents, in sufficient numbers to support statistical analysis, as favorably (i.e., cruise and license/maritime instruction) or negatively (i.e., mandatory regimental activity, taps, morning or afternoon formations, and watch) impacting their academic performance. This study found no statistical evidence to suggest the level of presenteeism, measured with the PPAP Scale, among the study’s sample of license students is associated with factors perceived to favorably or negatively impact academic performance. Additional insight can be gained from license student participants’ responses to the study’s open-ended questions (e.g., a perceived imbalance between time available to allocate to their academics and time needed to fulfill regimental responsibilities).  相似文献   

4.
This study compares the evolution of container port systems in China and the USA in terms of port throughput, number of container ports and the concentration level in the container port system, based on the time-series data on these three features over the period 1979–2009 for China and 1970–2009 for the USA. The results show that the densities of container ports in the two countries are similar, and their evolutionary processes are alike, which has led to a comparable market structure in the port industries of the two countries. In addition, the disparities between container ports closely represent the unevenness in the regional economic development. We further compare the port management regimes of the two countries in terms of the administrative processes for port development and expansion, the ownership structure and the providers of port functions, which offer some explanation on the dynamics of port evolution in the two countries. In conclusion, it can be seen that the evolution of the container port system and the management regime in the USA can be a de facto reference for the future development of the Chinese container port system.  相似文献   

5.
Coastal zones are among the most productive areas in the world, offering a wide variety of valuable habitats and ecosystems services. Despite the low population density in the Brazilian coastal zone, their distribution is quite concentrated near some coastal cities and state capitals. This concentration places enormous pressure on coastal resources. Therefore, the main objective of this paper is to present an overview on the current status of SiMoCo (Sistema de Monitoramento Costeiro, or Coastal Monitoring System in English) project as a possible early warning system that can be integrated to the Brazilian Coastal Management Information System. This prototype platform provides a real-time access to the composition, organization and simulation of planktonic communities. First, our results demonstrate such a system detecting a target dinoflagellate; second, we apply structural and functional indexes to compare and characterize the ecological networks from two different coastal areas. Conclusions are made about SiMoCo’s feasibility and its possible contribution to the decision-making process within integrated coastal zone management (ICZM) strategies.  相似文献   

6.
This paper addresses the issues of an increasingly competitive towage industry in Northern European ports. Enhanced competitiveness reflects the trends in the global mobility of capital, labour, enterprise and management within the context of deregulated port markets. Up until the early 1990s, the long term trend in major North European ports had been towards market concentration. Many small towage firms have been taken-over, bought out or merged. Alternatively, a pattern of consortia has emerged with co-operation and market sharing seen as preferable to ruinous competition. A contrasting trend has occurred in the 1990s, with new entrants into hitherto stable markets. In a number of ports—Antwerp, Rotterdam, Bremerhaven, Hamburg, Southampton, Thamesport, Bristol Channel—new fleets have brought competitive challenge to the incumbent towage fleets. The process of enhanced competitiveness raises questions of safety, reliability, investment and professionalism. The movement towards an openly competitive shipping industry has been in evidence from the 1960s onwards. The momentum of a dynamic shipping industry, with its competitiveness sharpened by the use of global supply factors, has intensified from that period. The movement in European tonnage towards flags of convenience and global labour supplies began in the tanker and bulk carrier markets; more recently this has spread to deep sea liner, short sea and even cabotage trade shipping. The towage industry is the last North European shipping sector to make this transition, following the trends towards port deregulation in the 1990s. From this perspective, this paper considers the impact on the towage market of global mobility and deregulation in North European towage markets—the impact of increased competition on the traditional operators and the likely effect on operational towage standards.  相似文献   

7.
This paper addresses the issues of an increasingly competitive towage industry in Northern European ports. Enhanced competitiveness reflects the trends in the global mobility of capital, labour, enterprise and management within the context of deregulated port markets. Up until the early 1990s, the long term trend in major North European ports had been towards market concentration. Many small towage firms have been taken-over, bought out or merged. Alternatively, a pattern of consortia has emerged with co-operation and market sharing seen as preferable to ruinous competition. A contrasting trend has occurred in the 1990s, with new entrants into hitherto stable markets. In a number of ports Antwerp, Rotterdam, Bremerhaven, Hamburg, Southampton, Thamesport, Bristol Channel new fleets have brought competitive challenge to the incumbent towage fleets. The process of enhanced competitiveness raises questions of safety, reliability, investment and professionalism. The movement towards an openly competitive shipping industry has been in evidence from the 1960s onwards. The momentum of a dynamic shipping industry, with its competitiveness sharpened by the use of global supply factors, has intensified from that period. The movement in European tonnage towards flags of convenience and global labour supplies began in the tanker and bulk carrier markets; more recently this has spread to deep sea liner, short sea and even cabotage trade shipping. The towage industry is the last North European shipping sector to make this transition, following the trends towards port deregulation in the 1990s. From this perspective, this paper considers the impact on the towage market of global mobility and deregulation in North European towage markets the impact of increased competition on the traditional operators and the likely effect on operational towage standards.  相似文献   

8.
Journal of Marine Science and Technology - Artificial intelligence is an enabling technology for autonomous surface vehicles, with methods such as evolutionary algorithms, artificial potential...  相似文献   

9.
Abstract

Most scenery evaluation methodologies incorporate visibility extent. In New York's coastal zone, visibility mapping for planning and project studies is complicated by low topographic relief, and diverse configurations of water edge and upland surface character. A generalized visibility model has been developed, including macrolandscape, observer, and sight‐line recording. Based on a prior shorescape study of New York's coast, the Lake Ontario Port Bay site was selected to test alternative visibility methods. Within the study site, four “landscape control points”; were chosen which provided extensive views of representative land and water forms, and surface types. For each control point, four families of visibility mapping approaches were applied: primary (field observation); secondary (topographic maps and vertical air photo analysis); tertiary (physical topographic model); and quaternary (digital terrain computer model). Major study conclusions are: the methods require different resources; all methods readily produced visibility maps; all methods, except secondary, could be used to produce perspective scenes for subsequent content evaluation; all methods except primary omitted one or more elements of the general visibility model; all methods should incorporate field work due to critical viewer environment conditions; sensitivity analysis in each method produced ambiguous zones; each view map was different, particularly in the background. An integrated, multi‐approach strategy would appear desirable for most planning and project applications.  相似文献   

10.
Abstract

This study examines the relationships of four general landscape characteristics to viewer preference for a coastal landscape including oil and gas development. Landscape management possibilities that address these characteristics are apparent naturalness, compatibility of development with its setting, and ephemeral characteristics, including tidiness.

Forty residents of and visitors to a Louisiana Gulf Coast island were interviewed. They were asked to describe and rate the attractiveness of local views. Three hundred and ninety‐three views containing a total of 99 features were described. A content analysis determined which of the 99 features were present in each view. Then factor analysis was performed on the feature presence classifications to suggest viewtypes. The 26 factors, or viewtypes, resulting were related to view ratings in a regression analysis.

Results suggest that, while natural‐appearing coastal landscapes are attractive, some developed landscapes may also be attractive. Compatibility, nighttime viewing, and tidiness enhance the attractiveness of developed landscapes. Where these characteristics become part of the design and maintenance program for oil and gas facilities, viewer preference may increase.  相似文献   

11.
Three different versions of a baroclinic three-dimensional circulation model of the North Sea are used to obtain information on the wind and density interactions in the North Sea ROFIs (Regions Of Freshwater Influence): the standard version with fully prognostic treatment of salinity and temperature is compared to a barotropic model run on the same grid on the one hand and to an also fully prognostic model run on a four times coarser grid on the other hand. In order to gain knowledge on the wind and density interactions, two opposing wind directions are chosen for investigation, namely a time of strong north wind, 21st–28th April 1982, and a time of strong southwest wind, 22nd–24th May 1982. In the April case the effect of the salinity gradients on the border of the ROFIs of Rhine, Weser, Ems and Elbe, i.e. along the continental shore, is shown to lead to a clear enhancement of the mean surface currents. In May this result is partly disguised by the additional effect of the thermocline in the deeper parts of the North Sea, i.e. in the classical shelf sea regime region. Nevertheless, the same pattern of enhanced mean surface currents along the coast is detected and is of the same order of magnitude as in the April case. It is thus concluded that although the circulation in the North Sea is reversed by the wind, the density induced component of the general circulation is modified only slightly.  相似文献   

12.
13.
Abstract

the prospect of global warming and consequent sea level rise will have important implications for coastal communities. this article examines the land use implications of alternate sea level rise scenarios on the city of myrtle beach, south carolina. current trends as well as high and low sea level rise scenarios are superimposed on the city's beach profile and near shore contours to estimate the type and value of land development likely to be impacted.

It is found that losses associated with accelerated sea level rise would be particularly high in the city's hotel district and that overall property loss could range from 21 to 60% of the city's total property value. to lessen these potential losses, coastal communities such as myrtle beach must choose among one of three policy options including: (1) barricade the beach, (2) raise the land, and (3) implement a strategic retreat. specific alternatives within each of these options are explored in turn. the article concludes that successful development plans will incorporate ground rules sensitive to and consistent with dynamic coastal processes.  相似文献   

14.
The general trend in ecosystem modelling is to improve the spatial resolution by shifting from rough box-models to fine 3D models. Despite the continuous speeding-up of computing, 3D models involving numerous state variables may remain intractable, especially for parameter calibration, when processes with long half-life periods (i.e, from years to decades) are introduced, such as the behaviour of organic matter in sediment and population dynamics of benthic species. In these cases, a first approach can be provided by fast-running box-models, if they take into account the most crucial hydrodynamic properties of the system. In a macrotidal shelf sea such as the English Channel, the long-term horizontal transport can be summarized by the tidal residual circulation, and the vertical stratification can be sketched by a two- or three-layered integral model.This paper compares the results obtained in the English Channel area by the same biogeochemical equations of pelagic primary production, coupled to 1) a two-layered box-model 2) a three-layered box-model (i.e., with an intermediate cline layer between surface and bottom ones) and 3) a fine-gridded 3D model. Comparison is focused firstly on thermal stratification and summer dinoflagellate blooms in the north-western Channel and secondly on the haline stratification and the sequence of blooms obtained in the eutrophicated Seine river plume. Comparison shows that box-models act as low-pass filters which reproduce correctly the weekly mean time-course, but greatly reduce the variance locally observed in a tide-oscillating plume region. As far as global characteristics are concerned, such as the annual primary production, or the percentage of variation in annual production after reducing the nutrient loadings, the box and 3D models gave very similar results. This conclusion reinforces the usefulness of using box-models as a first approach in long-term processes, for which a long transient phase is expected before reaching the annual periodic solution.  相似文献   

15.
16.
ABSTRACT

Transport costs are useful explanatory variables in port choice research. Nevertheless, the availability of such information usually poses a problem. Thus, the formulation of an alternative approach, to be used as a proxy of these variables, would be desirable. The objective of this study is to improve the analysis of container port choice using logit models by adopting physical non-monetary indicators based on maritime distance and ship size. The statistical tests of logit models on port choice using these new variables are compared with the result of using cost variables for the same data set of choice positions. The statistical outcome is good and allows us to present this new approach as a contribution to the literature on port choice modeling.  相似文献   

17.
This paper describes a comparative study between full scale measurements recorded on a fast patrol boat encountering heavy winter seas, south of the Isle of Wight and theoretical predictions accounting for the slamming behaviour of the flexible hull. A hydroelastic approach is adopted and satisfactory agreement between measured and predicted responses demonstrated.  相似文献   

18.
Two major environmental problems currently affecting the Louisiana coastal zone are a high rate of wetland loss and high levels of surface water pollution. The application of secondarily treated wastewater to wetlands can be a means of dealing with both of these problems. The benefits of wetland wastewater treatment include improved surface water quality, increased accretion rates to balance a high relative water level rise due mainly to subsidence, improved plant productivity and habitat quality, and decreased capital outlays for conventional engineering treatment systems. Wetland treatment systems can, therefore, be designed and operated to restore deteriorating wetlands. Hydrologically altered wetlands, which are common in the Louisiana coastal zone, are appropriate for receiving municipal and some types of industrial effluent. While the U.S. Environmental Protection Agency has determined wetland wastewater treatment is effective in treating municipal effluent, it has discouraged the use of natural wetlands for this purpose. At the same time, funds are being used for the construction of artificial wetlands to treat municipal effluent. In the Louisiana coastal zone, however, wetlands are deteriorating and disappearing due to hydrological alteration and a high rate of relative sea level rise. If no action is taken, these trends will continue. Effluent discharge to existing wetlands should be incorporated into a comprehensive management plan designed to increase sediment and nutrient input into subsiding wetlands in the Louisiana coastal zone, improve water quality, and result in more economical waste‐water treatment. The authors believe that the Louisiana example serves as a model for other coastal areas especially in light of projections of accelerated sea level rise.  相似文献   

19.
20.
Separation from partner and family has been found to be one of the most significant causes of stress for seafarers, with separation from the family one of the most important 'stress' factors influencing a decision to reduce planned sea service. Drawing on in-depth interviews with seafarers' partners in the UK, China and India, this paper focuses on the impact of seafaring on family life, with particular attention given to the effects of differing conditions of service and the range of company support available to seafarers and their partners. The paper concludes that the negative consequences of seafaring can be minimized by such policies as shorter trips, continuous employment (rather than employment by voyage) and opportunities for partners and families to sail. Whilst these measures may have financial costs, these can be off-set by improved retention of seafarers and the avoidance of stress-related illnesses. Indeed, at a time when there is a projected shortfall of well-trained seafarers, such steps may be sound company policy  相似文献   

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